The short answer is NO, you cannot update it and remove the original.
The best answer is to use CM to:-
select (highlight) your copy of the original route (the one on the DLS)
open the Content Menu
select Create New Version
This will "up-version" the layout kuid to the next number in the sequence - e.g. <kuid:1234:5678> will become <kuid2:1234:5678:1> or, if the original had already been "up-versioned" (e.g. to <kuid2:1234:5678:1>) then it will become the next number in the kuid2 sequence (e.g. <kuid2:1234:5678:2>) etc. You can then work on the new "up-versioned" layout to make whatever changes you want. When finished, upload the new version to the DLS.
The original version will still remain on the DLS for those who prefer to use it (and there will be some users who will) but everyone who has that original version will have the opportunity to download and install the new version. They will have both versions installed and can choose to either delete the older version or keep it and have both. The older version will be labelled "Installed from DLS, Obsolete".
You create and upload a route. It is downloaded and used by others. Some of those users create sessions based on your route and some of those sessions are uploaded to the DLS - which is perfectly legal because their sessions only reference your route, they do not copy it. Users who download these sessions will also download and install your original route.
Assuming that it was possible for you to delete your own work from the DLS (the "theoretical" part of the scenario) and for some reason you did delete the route, what would be the result? Suddenly all those DLS sessions by other creators based on your route will now have a "missing dependency", your route. The creators of those sessions are going to be angry because all their work would have been wasted and they will look bad for uploading an asset with a missing dependency. They will be looking for someone to blame and guess who that will be? It will probably, initially at least, be N3V but fear not, they will eventually get round to you.
You could argue that you have provided an update to the route but that update could very easily have changes that will make the sessions useless or faulty - and again who will get the blame?
N3V will only remove an asset from the DLS if there is a clear and confirmed copyright violation (and perhaps for one or two other very rare reasons). The original creator changing her/his mind over the upload for whatever reason is not a cause for removal.
